Antibodies with enhanced ADCC capacity are an emerging species in the field of cancer therapy. It has been recognized that the so-called effector functions of an antibody, which are mediated by its Fc region, are an important mechanism of action in antibody-based cancer therapy. Of particular importance in this context is antibody-dependent cellular cytotoxicity (ADCC), the destruction of antibody-coated target cells (e.g. tumor cells) by NK (natural killer cells) and other immune effector cells, which is triggered when antibody bound to the surface of a cell interacts with activating Fc receptors on the effector cell.
Enhancing the ADCC activity of therapeutic antibodies has therefore become of great interest and various methods for ADCC enhancement have been described. For example, Shields et al. (J Biol Chem 9(2), 6591-6604 (2001)) showed that amino acid substitutions at positions 298, 333, and/or 334 of the Fc region (EU numbering of residues) improve ADCC. Alternatively, increased Fc receptor binding and effector function can be obtained by altering the glycosylation of an antibody. IgG1 type antibodies, the most commonly used antibodies in cancer immunotherapy, have a conserved N-linked glycosylation site at Asn 297 in each CH2 domain of the Fc region. The two complex biantennary oligosaccharides attached to Asn 297 are buried between the CH2 domains, forming extensive contacts with the polypeptide backbone, and their presence is essential for the antibody to mediate effector functions including ADCC (Lifely et al., Glycobiology 5, 813-822 (1995); Jefferis et al., Immunol Rev 163, 59-76 (1998); Wright and Morrison, Trends Biotechnol 15, 26-32 (1997)). Umaña et al. (Nat Biotechnol 17, 176-180 (1999) and U.S. Pat. No. 6,602,684 (WO 99/54342), the contents of which are hereby incorporated by reference in their entirety) showed that overexpression of β(1,4)-N-acetylglucosaminyltransferase III (GnTIII), a glycosyltransferase catalyzing the formation of bisected oligosaccharides, in Chinese hamster ovary (CHO) cells significantly increases the in vitro ADCC activity of antibodies produced in those cells. Overexpression of GnTIII in production cell lines leads to antibodies enriched in bisected oligosaccharides, which are generally also non-fucosylated and of the hybrid type. If in addition to GnTIII, mannosidase II (ManII) is overexpressed in production cell lines, antibodies enriched in bisected, non-fucosylated oligosaccharides of the complex type are obtained (Ferrara et al., Biotechn Bioeng 93, 851-861 (2006)). Both types of antibodies show strongly increased ADCC, as compared to antibodies with unmodified glycans, but only antibodies in which the majority of the N-glycans are of the complex type are able to induce significant complement-dependent cytotoxicity (Ferrara et al., Biotechn Bioeng 93, 851-861 (2006)). The elimination of fucose from the innermost N-acetylglucosamine residue of the oligosaccharide core appears to be the critical factor for the increase of ADCC activity (Shinkawa et al., J Biol Chem 278, 3466-3473 (2003)). Therefore, further methods for producing antibodies with reduced fucosylation were developed, including e.g. expression in α(1,6)-fucosyltransferase deficient host cells (Yamane-Ohnuki et al., Biotech Bioeng 87, 614-622 (2004); Niwa et al., J Immunol Methods 306, 151-160 (2006)).
T cells are another major immune cell population which are highly effective in killing cancer cells. The contribution of T cells in fighting cancer cells has been established from several cancer indications, including colorectal cancers (CRC), non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (NHSCC). See for example Galon et al. 2006, Fridman et al. 2011, Halama et al. 2011, Hiraoka et al. 2006, Al-Shibli et al. 2008, Kawai et al. 2008, Welsh et al. 2005, Dieu-Nosjean et al. 2008, Brandwein-Gensler et al. 2005, Zhang et al. 2010, Badoual et al. 2006, Rajjoub et al. 2007, and Le et al. 2005.
Several ADCC-enhanced antibodies, including the glycoengineered anti-EGFR antibody imgatuzumab, as well as the glycoengineered anti-CD20 antibody obinutuzumab and a glycoengineered anti-Her3 antibody (WO 2011/076683; US20110171222) have shown promising results in clinical development. However, despite the great potential of ADCC-enhanced antibodies, in particular for cancer therapy, a diagnostic assay for selection of those patients which will most benefit from treatment with such antibodies has yet to be generated. In view of the potential adverse effects associated with ineffective cancer therapies, it is generally acknowledged that there is a need for individualizing cancer treatment.
Therefore, it is an aim of the present invention to provide methods for determining which patients respond particularly well to ADCC-enhanced antibody therapy.